Time fuse



S. FARROW Nov. 16, 1943.

TIME FUSE Filed April 4, 1938 Inventnr StanlayFarruW At turns TIME FUSE I -Stanley Farrow, Denvillc, N. .L, assignor tothe Government of .the United'zStates of America,-.:

' i represented by the-Secretary of War Application April 4, 1938, Serial No. 1'99;8' 9i f I e'Claims. (,Cl. 102-82) I 4 (Granted under the "act of March '3, 1883, amended April 30, 1928; 3700. G. 757) The invention described herein may be manufactured and used; by I or for the Government for'governmental purposes, without the payment to-m'e of any royalty thereon;

. This invention relates to" a. time fuse.

The purpose ofthe invention is to provide an inexpensive and easily assembled time fuse in which ignition may be-instituted inside of a containerjunaffected by temperature, humidity andlbarometric pressure or by velocity and rotation of the projectile.

' This is accomplished by placing a catalyst and a gaseous reactant in separate chambers,

' arrangingterrelease'of the gaseous reactant and providing for timed regulation of the passage of the gas into contact with the catalyst in sufficient concentration to heat it and produce ignition.

To these and other ends, the invention consists in the construction, arrangement and combination of elements described hereinafter and. pointed out in the claims forming a part of this specification.

A practical embodiment of the invention is V illustrated in the accompanying drawing, where- Fig. 1 is a longitudinal sectional view, partly in elevation, of a fuse constructed in accordance with the invention;

Fig. 2 is a plan view of the movable disk;

Fig. 3 is a plan view of the fixed disk;

Fig. 4 is a longitudinal sectional view showing the application of the invention to an impact fuse;

Fig. 5 is an enlarged sectional view of the head of the fuse of Fig. 4;

Fig. 6 is a sectional view of a unit in which a low pressure gas is used.

Referring to Figs. 1 to 3 there is shown a fuse casing comprising a body 5 having a counterbored recess to provide an inner chamber 6 and to receive in its outer portion a head 1 which has'a chamber '8 in its inner end. The head is arranged for rotation with respect to ,the body and to this end it is formed with an annular groove 9 which receives the inner ends of pins Ill-40 carried bythe body.

The body 5 carries a catalyst H such as platinum sponge, one portion of which is exposed mouth closed by a plug '15. A closed container l6 held in the rear end of the cham'berldin any convenient manner is filled with a gas,-'such-as hydrogen, which is capable of causing'the catalyst llto'become heated and produce ignition of the gasor' the charge 12'. The means for breaking the co'ntainer'to release the gasconsistsof a plunger ll having'a point 18 andth'e gas when'released'fiows to the chamber 8 through passageslil formedin the headl. The plunger is normally held in the mouth of the chamber M by means of a-resilientsplit'ring 20 which is partially disposed within a groove 2| inrthe plunger and engages the lip 22 ofthe chamber. When a projectile equipped with l the fuse is fired from a gun, the force of set-back causes the, plunger to be driven rearwardly out of the grasp of the split ring 20 and puncture the container.

A pair of disks 23 and 24 constituting a valve, are interposed between the chambers 6 and 8 and are attached respectively to the body 5 and head I by screws 25 and 26. The disk 23 is provided in one-half of its surface with a plurality of small apertures 21, while the disk 24 is provided with a single semi-circular opening 28.

When the disks are arranged so that the solid tion of the disk 23 communication between the chambers 6 and 8 is interrupted. By rotating the head 1 and with it the disk 24, the number of apertures 26 establishing communication between the chambers 8 and 6 may be regulated. This adjustment determines the rate of flow of gas from the chamberB to'the chamber 6 and may be interpreted in units of time which are indicated externally of the fuse by means of a time scale 29 which is inscribed on the head and read against an index 30 on the body.

In the above illustration, the gas in the container i6 is under high pressure with a relatively large pressure difference existing between the chambers 6 and 8. The rate of flow through the apertures 27 will be dependent of the ratio of pressures and will be constant according tothe law of the flow of gases.

ring 36. On impact of the fuse the plunger moves.

forwardly due to inertia and punctures the container 3|. The period or delay before heating of the catalyst 31 to produce ignition may be 2,884,182 f 2 a I W chamber," a container in"the'"other-chamber controlled by a valve mechanism as in Fig. 1 0r by regulating the flow of the gas through appropriately dimensioned passages 38 in the plunger.

In the more orless schematic illustration of Fig. 6 thecontainer 38 is fllled with a gas under lowpressure. The chamber 40 in which the'con- I tainer 39 is placed is oivsuch size that the pres:

sure of the gas upon being released drops to about one-half of its original pressure; [A mem-' I brane ordiaphragm 4| separating, the-chamber 40 iromthe chamber 42 containing the catalyst 43 is made of a porous material-such as fabric. With the rate 01' difiusion of the gas through the diaphragm being known the time required for the gas to be present in chamber '42- in sufllcient.

carrying a gas under pressure and capable of reacting with the catalyst'to cause it to heat and produce ignition; intertial means for. opening the" container in response to acceleration or said fuse nd, mew o r d an ma n fi varying the rate to! flow of gas into the chamber containing the catalyst whereby the time required i 1 to produce ignitionafter said container is opened may be varied. r

3. In a lose, 'a catalyst, a container carrying a gas-under pressure and capable'oi reacting 'contact'with the catalyst whereby the time reconcentration to react on the catalyst maybe hastened The container is'arranged to be tured on.set-:back;of a plunger;;,- L;.,I;Ol81mZ v v Q1. Ina fuse, a base, a catalyst-in the base, a head rotatably carried by the base, a container in the head carrying a gas under pressure'andcapable of reacting-with,the-catalyst to cause it to heat and produce ignition, means for open ing the, container at a predetermined time; and valved means between the catalystand container constructedand arrangediorv varying the rate of flow of .gas :into. contact iwith the catalyst whereby the time required to produce ignition after saidscontainer is opened may be varied.

a. '2. Aifuse having-chambers, a catalyst in one chamben-a sealed container carrying a'gas-under opened maybe varied.

v quired to produceignition after said'container is readily determined. It a vacuum is created inflfj chamber 42, thepassage oi the gas into it will be 42 In combination, ashell, a fuse comprising, 7

a chamber, aflnely dividedatalyst 'inusaid pressure and capable of reacting'with-said cata-; lyst to cause it toxrheat andprodue ignition, inertial means for, puncturing-said container-in response 1 to. Jaccelerationf or said 7 .shell, valve means interposed between said ;chamber and I 7 said container constructed and arranged for pre,-.

determining the rate, or flow of said gas into said chamber and into contact. withisaid catalyst whereby the time required to produce ignitton. c after the ssaid#container.ispunctmed, may; be 

